Next, on submitting a score, it went to an all white page with some html parsed on it. No css at all what so ever.

And here it is with the following fix in place

Here is the fix:
OPEN plugins/activity/templates/default/saved_body.tpl
FIND
ADD BEFORE
FIND
AFTER ADD
CLOSE AND SAVE FILE
Now your no css problem is fixed after you clear the cache.
The next issue is if you do not have enough credits to play a game , (ONLY if you have Cash Mod installed and enabled in Activity Mod), it takes you to a page that nicely explains you do not have enough credits or what ever to play the game. It has a Javascript Close Page link that does not work.
Here is the fix for English and Italian versions.
OPEN plugins/activity/language/lang_english/lang_activity.php
FIND LINE 121
REPLACE WITH
FIND LINE 122
REPLACE WITH
CLOSE AND SAVE FILE
OPEN plugins/activity/language/lang_italian/lang_activity.php
FIND LINE 122
REPLACE WITH
FIND LINE 123
REPLACE WITH
CLOSE AND SAVE FILE
And that will fix your pages from not closing and returning you to the games page.
PLEASE NOTE: My fixes are not official. That is up to MG to decide what is right. This is just what worked for me :-)
Take care and have a great night all. Off to bed I go. I'm tired.